Reciprocating piston pump serviceable without tools

ABSTRACT

The “no tools” pump removal system comprises a bearing housing attached to the drive housing. The bearing housing has a hinged door that when opened allows removal of the pump pin and thence the pump. The bearing housing is provided with a latch assembly and a handle. A safety latch retains the handle in place during operation and until it is desired to remove the pump.

RELATED APPLICATIONS

This application claims the benefit of U.S. Application Ser. No. 60/693,254 filed Jun. 23, 2005.

BACKGROUND OF THE INVENTION

Airless sprayers having reciprocating piston pumps are popular for applying architectural coatings. One problem with prior art pumps is the need to use tools to service such pumps when it comes to installation and removal.

SUMMARY OF THE INVENTION

The “no tools” pump removal system comprises a bearing housing attached to the drive housing. The bearing housing has a hinged door that when opened allows removal of the pump pin and thence the pump. The bearing housing is provided with a latch assembly and a handle. A safety latch retains the handle in place during, operation and until it is desired to remove the pump.

To remove, first the pressure in the pump is relieved (using the mechanism present in all airless pumps) and then the paint hose is removed by unscrewing the ribbed fitting and fine thread by hand. At that point, the safety latch is lifted and the handle swung outwardly releasing the u-bolt latch from the door. If the door will not swing freely outwardly (because of accumulated dried paint), the u-bolt may be positioned on the near side of the door and used to lever it outwardly to unstick the door. At this point, the pump pin can be grasped and removed which allows the pump to drop straight down for replacement or repacking.

To install the pump, the pump pin can be placed in the rod and then placed in the pin holder on the door to pull the rod out to the proper position such that the top of the collar on the pump cylinder is nearly against the mating shoulder in the bearing housing. The pump can then be positioned on the connecting rod and the pin slid into place. The door is then swung shut and the latch u-bolt placed over the door latch protrusion and the handle swung shut. The safety latch may then be operated.

It should be noted that the pump cylinder is supported only on top in the bearing housing cavity which allows the pump to drop during removal. The door supports the top and bottom of the pump cylinder taking up all of the downward force. The pump cylinder has a collar that slides into the bearing housing and has flat (not tapered) surfaces on top and bottom to prevent the collar from wedging into the bearing housing. An adjustment screw is provided where the door latches into the bearing housing to reduce unwanted movement.

These and other objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.

A BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the pump of the instant invention.

FIG. 2 is a perspective showing the instant invention with the safety latch swung opened.

FIG. 3 is a perspective showing the instant invention with the handle being swung open.

FIG. 4 is a perspective showing the instant invention showing the door being ratcheted open.

FIG. 5 is a perspective showing the instant invention with the u-bolt being repositioned.

FIGS. 6 and 7 are perspectives showing the instant invention with the u-bolt being, used to unstuck a stuck door.

FIG. 8 is a perspective showing the instant invention with the door being opened.

FIG. 9 is a perspective showing the instant invention with the pump pin being pulled.

FIG. 10 is a perspective showing the instant invention showing the pump being installed.

FIG. 11 is a perspective showing the instant invention with the pump pin being installed.

FIG. 12 is a cross-section showing the pump of the instant invention installed in the bearing housing.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the instant invention, the “no tools” pump removal system comprises a bearing housing 12 attached to the drive housing 14 of an airless sprayer 10 which also has a power source 16. The bearing housing 12 has a hinged door 18 that when opened allows removal of the pump pin 20 and thence the pump 22. The bearing housing 12 is provided with a latch assembly 24 and a handle 26. A safety latch 28 pivots and releasbly retains the handle 26 in place during operation and until it is desired to remove the pump 22. To remove, first the pressure in the pump 22 is relieved (using the mechanism present in all airless pumps) and then the paint hose 30 is removed by unscrewing the ribbed fitting 32 and fine thread 34 by hand. At that point, the safety latch 28 is lifted and the handle 26 swung outwardly releasing the u-bolt latch 36 from the door 18. If the door 18 will not swing freely outwardly (because of accumulated dried paint), the u-bolt may be positioned on the near side 18 a of the door 18 as shown in FIG. 6 and used to lever it outwardly to unstick the door 18. At this point, the pump pin 20 can be grasped and removed which allows the pump 22 to drop straight down for replacement or repacking.

To install the pump 22, the pump pin 20 can be placed in the rod 38 of pump 22 and then placed in the pin holder 40 on the door 18 to pull rod 38 out to the proper position such that the top of the collar 46 on the pump cylinder 44 is nearly against the mating shoulder 12 a in the bearing housing 12. The pump can then be positioned on the connecting rod 42 and the pin 20 slid into place. The door 18 is then swung shut and the latch u-bolt 36 placed over the door latch protrusion 18 b and the handle 26 swung shut. The safety latch 28 may then be operated.

It should be noted that the pump cylinder 44 is supported only on top in the bearing housing cavity at shoulder 12 a which allows the pump 22 to drop during removal. The door 18 supports the top 22 a and bottom 22 b of the pump cylinder 22 taking up all of the downward force. The pump cylinder has a collar 22 c that slides into the bearing housing and has flat (not tapered) surfaces on top 22 a and bottom 22 b to prevent the collar 22 c from wedging into the bearing housing 12. A adjustment screw 48 is provided where the door 18 latches into the bearing housing 12 to reduce unwanted movement.

It is contemplated that various changes and modifications may be made to the pump without departing from the spirit and scope of the invention as defined by the following claims. 

1. A reciprocating piston pump for attachment to a drive and having a rod, a cylinder and a bearing housing, the improvement comprising a door hingedly attached to said bearing housing so as to releasably sandwich said cylinder between said bearing housing and said door.
 2. The reciprocating piston pump of claim 1 where said cylinder comprises a cylindrical shoulder for mating with said bearing housing and said door.
 3. The reciprocating piston pump of claim 2 wherein said shoulder comprises upper and lower ends.
 4. The reciprocating piston pump of claim 3 wherein said bearing housing comprise a shoulder for mating with said cylinder upper shoulder.
 5. The reciprocating piston pump of claim 4 wherein said door comprises an annular groove for mating with said cylinder upper and lower shoulders.
 6. The reciprocating piston pump of claim 1 further comprising a latch mechanism for securing said door to said bearing housing.
 7. The reciprocating piston pump of claim 6 wherein said latch mechanism comprises a latch member and is operable between a first position securing said door to said bearing housing and a second position where said door may be swung open from said bearing housing.
 8. The reciprocating piston pump of claim 7 wherein said larch mechanism comprises a protrusion on said door having first and second sides, said latch member cooperating with said protrusion first side to maintain said, door in said first position and said latch member cooperating with said protrusion second side to force said door outwardly into said second position.
 9. The reciprocating piston pump of claim 1 wherein said door comprises a distal end remote from said hinged attachment, said bearing housing comprising a screw for adjusting friction engagement tension between said distal end and said bearing housing.
 10. The reciprocating piston pump of claim 1 wherein said drive mechanism comprises a connecting rod and said pump further comprising a pump pin manually releasably connecting said rod and said connecting rod. 